CN115300929A - Crystallization equipment and method for phenylacetic acid production - Google Patents
Crystallization equipment and method for phenylacetic acid production Download PDFInfo
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- CN115300929A CN115300929A CN202210973352.XA CN202210973352A CN115300929A CN 115300929 A CN115300929 A CN 115300929A CN 202210973352 A CN202210973352 A CN 202210973352A CN 115300929 A CN115300929 A CN 115300929A
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- WLJVXDMOQOGPHL-UHFFFAOYSA-N phenylacetic acid Chemical compound OC(=O)CC1=CC=CC=C1 WLJVXDMOQOGPHL-UHFFFAOYSA-N 0.000 title claims abstract description 204
- 238000002425 crystallisation Methods 0.000 title claims abstract description 140
- 230000008025 crystallization Effects 0.000 title claims abstract description 129
- 229960003424 phenylacetic acid Drugs 0.000 title claims abstract description 101
- 239000003279 phenylacetic acid Substances 0.000 title claims abstract description 101
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims description 44
- 239000000243 solution Substances 0.000 claims abstract description 124
- 230000020477 pH reduction Effects 0.000 claims abstract description 95
- 238000001816 cooling Methods 0.000 claims abstract description 73
- 239000002253 acid Substances 0.000 claims abstract description 71
- ITIONVBQFUNVJV-UHFFFAOYSA-N Etomidoline Chemical compound C12=CC=CC=C2C(=O)N(CC)C1NC(C=C1)=CC=C1OCCN1CCCCC1 ITIONVBQFUNVJV-UHFFFAOYSA-N 0.000 claims abstract description 64
- 229940006198 sodium phenylacetate Drugs 0.000 claims abstract description 64
- 239000003507 refrigerant Substances 0.000 claims abstract description 56
- 239000007789 gas Substances 0.000 claims abstract description 50
- 239000012267 brine Substances 0.000 claims abstract description 46
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims abstract description 46
- 238000011282 treatment Methods 0.000 claims abstract description 22
- 239000002912 waste gas Substances 0.000 claims abstract description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 39
- 229910001868 water Inorganic materials 0.000 claims description 39
- 239000007788 liquid Substances 0.000 claims description 32
- 230000008569 process Effects 0.000 claims description 30
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 24
- 238000003756 stirring Methods 0.000 claims description 24
- 239000011780 sodium chloride Substances 0.000 claims description 20
- 239000012452 mother liquor Substances 0.000 claims description 19
- 230000007246 mechanism Effects 0.000 claims description 18
- 230000001105 regulatory effect Effects 0.000 claims description 16
- 239000013078 crystal Substances 0.000 claims description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 229910002804 graphite Inorganic materials 0.000 claims description 11
- 239000010439 graphite Substances 0.000 claims description 11
- 230000001276 controlling effect Effects 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 238000001514 detection method Methods 0.000 claims description 5
- 238000005265 energy consumption Methods 0.000 abstract description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 47
- 238000006243 chemical reaction Methods 0.000 description 27
- 239000000047 product Substances 0.000 description 22
- 238000000926 separation method Methods 0.000 description 19
- 238000011084 recovery Methods 0.000 description 14
- 230000008901 benefit Effects 0.000 description 13
- 239000012071 phase Substances 0.000 description 12
- 239000003054 catalyst Substances 0.000 description 11
- 239000000463 material Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 238000005406 washing Methods 0.000 description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- WLJVXDMOQOGPHL-PPJXEINESA-N 2-phenylacetic acid Chemical compound O[14C](=O)CC1=CC=CC=C1 WLJVXDMOQOGPHL-PPJXEINESA-N 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 5
- 239000002826 coolant Substances 0.000 description 5
- 238000003912 environmental pollution Methods 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 159000000000 sodium salts Chemical class 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- LSBDFXRDZJMBSC-UHFFFAOYSA-N 2-phenylacetamide Chemical compound NC(=O)CC1=CC=CC=C1 LSBDFXRDZJMBSC-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- IPBVNPXQWQGGJP-UHFFFAOYSA-N acetic acid phenyl ester Natural products CC(=O)OC1=CC=CC=C1 IPBVNPXQWQGGJP-UHFFFAOYSA-N 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- PQILKFQDIYPBKI-UHFFFAOYSA-N azane;2-phenylacetic acid Chemical compound [NH4+].[O-]C(=O)CC1=CC=CC=C1 PQILKFQDIYPBKI-UHFFFAOYSA-N 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229940049953 phenylacetate Drugs 0.000 description 2
- JFOZPCWVLIBFCH-UHFFFAOYSA-M potassium;2-phenylacetate Chemical group [K+].[O-]C(=O)CC1=CC=CC=C1 JFOZPCWVLIBFCH-UHFFFAOYSA-M 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000003908 quality control method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 229930182555 Penicillin Natural products 0.000 description 1
- JGSARLDLIJGVTE-MBNYWOFBSA-N Penicillin G Chemical compound N([C@H]1[C@H]2SC([C@@H](N2C1=O)C(O)=O)(C)C)C(=O)CC1=CC=CC=C1 JGSARLDLIJGVTE-MBNYWOFBSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000006315 carbonylation Effects 0.000 description 1
- 238000005810 carbonylation reaction Methods 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- KXZJHVJKXJLBKO-UHFFFAOYSA-N chembl1408157 Chemical compound N=1C2=CC=CC=C2C(C(=O)O)=CC=1C1=CC=C(O)C=C1 KXZJHVJKXJLBKO-UHFFFAOYSA-N 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000012043 crude product Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- 229940049954 penicillin Drugs 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000011403 purification operation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 235000013599 spices Nutrition 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0063—Control or regulation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/02—Crystallisation from solutions
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D2009/0086—Processes or apparatus therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application discloses a crystallization device and a crystallization method for phenylacetic acid production, and belongs to the technical field of crystallization devices. A crystallization apparatus for phenylacetic acid production comprising: the system comprises a preheater, an acidification mixer, a buffer unit, a multi-stage cooling unit and a crystallization unit; the inlet of the preheater is connected with a brine conveying pipeline containing sodium phenylacetate; a first inlet of the acidification mixer is communicated with an outlet of the preheater, and a second inlet of the acidification mixer is connected with an acid liquor conveying pipeline; a third inlet of the buffer unit is communicated with an outlet of the acidification mixer, a tail gas outlet is communicated with the heat exchange device, and a noncondensable gas outlet is communicated with the waste gas treatment unit; the multistage cooling unit comprises a plurality of coolers connected in series, the coolers adopt different refrigerants, and a solution outlet of the buffer unit is communicated with an inlet of the multistage cooling unit; the outlet of the multistage cooling unit is communicated with the inlet of the crystallization unit, and phenylacetic acid is crystallized and precipitated in the crystallization unit. The application can improve the production efficiency, reduce the energy consumption, save the cost and facilitate the operation.
Description
Technical Field
The application belongs to the technical field of crystallization devices, relates to equipment related to phenylacetic acid production, and particularly relates to crystallization equipment and a method for phenylacetic acid production.
Background
Phenylacetic acid is an important fine chemical product, is widely applied to industrial production, such as the production of penicillin, and can be widely used as an intermediate of medicines, pesticides, spices and the like. In the related art, there are many methods for producing phenylacetic acid, and for example, sodium cyanide method, phenylacetamide method, oxo synthesis method, and the like have been industrially used.
In the production process of phenylacetic acid, various reaction raw materials are generally reacted, then products obtained by the reaction are separated, and then a series of treatments are required to be carried out on the separated mixture to obtain a phenylacetic acid product (pure product). To obtain industrial raw materials suitable for production, extraction and purification of phenylacetic acid are generally required, wherein a crystallization method is a common phenylacetic acid purification method. The crystallization method is as follows: the difference of the solubility of different components in the mixture in the solvent at different temperatures is utilized to realize the separation and purification operation method.
The traditional crystallization mode for phenylacetic acid production is mostly that the materials are all directly input into a kettle-type crystallization tank and operated in the kettle-type crystallization tank, and the problems of insufficient contact heat exchange of a refrigerant body, difficulty in operation control, high energy consumption and the like exist, so that the defects of unstable product quality, high production cost, low production efficiency and the like can be caused.
Disclosure of Invention
In view of the above-mentioned problems, the present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the crystallization equipment and the crystallization method for producing phenylacetic acid provided by the invention are beneficial to reducing energy consumption, saving production cost, improving production efficiency, facilitating operation and overcoming the defects in the prior art.
In order to solve the technical problem, the present application is implemented as follows:
according to one aspect of the present application, embodiments provide a crystallization apparatus for phenylacetic acid production, the crystallization apparatus comprising:
the inlet of the preheater is connected with a brine conveying pipeline containing sodium phenylacetate;
the acidification mixer comprises a first inlet and a second inlet, the first inlet is communicated with the outlet of the preheater, and the second inlet is connected with an acid liquor conveying pipeline;
the buffer unit comprises a third inlet, a tail gas outlet, a non-condensable gas outlet and a solution outlet, the third inlet is communicated with the outlet of the acidification mixer, the tail gas outlet is communicated with a heat exchange device for recovering tail gas, and the non-condensable gas outlet is communicated with a waste gas treatment unit for waste gas treatment;
the multi-stage cooling unit comprises a plurality of coolers connected in series, the coolers adopt different refrigerants, and a solution outlet of the buffer unit is communicated with an inlet of the multi-stage cooling unit;
a crystallization unit, wherein an outlet of the multistage cooling unit is communicated with an inlet of the crystallization unit, and phenylacetic acid is precipitated in a crystal form in the crystallization unit.
Optionally, the multistage cooling unit includes three coolers connected in series, the three coolers connected in series are a first-stage cooler, a second-stage cooler and a third-stage cooler respectively, an inlet of the first-stage cooler is communicated with the solution outlet of the buffer unit, and an outlet of the third-stage cooler is communicated with an inlet of the crystallization unit.
Optionally, the temperature of the refrigerant of the primary cooler is higher than that of the refrigerant of the secondary cooler, and the temperature of the refrigerant of the secondary cooler is higher than that of the refrigerant of the tertiary cooler; and/or temperature regulating valves are arranged on refrigerant connecting pipelines of the first-stage cooler, the second-stage cooler and the third-stage cooler.
Optionally, the refrigerant of the primary cooler is process circulating water with the temperature of 25-35 ℃, and the process circulating water is process circulating water generated in the whole phenylacetic acid production process; the refrigerant of the secondary cooler is centrifugal mother liquor with the temperature of 10-20 ℃, and the centrifugal mother liquor is centrifugal mother liquor separated by centrifugal equipment in a phenylacetic acid production system; the refrigerant of the third-stage cooler is chilled water with the temperature of 3-7 ℃.
Optionally, the crystallization unit comprises a crystallization tank and a first stirring mechanism arranged in the crystallization tank; and/or the buffer unit comprises an acidification buffer tank and a second stirring mechanism arranged on the acidification buffer tank; and/or the heat exchange device comprises a graphite heat exchanger.
Optionally, a solution outlet of the buffer unit is connected with an inlet of the multistage cooling unit through an acidified solution conveying pipeline, and a conveying pump is arranged on the acidified solution conveying pipeline; the buffer unit further comprises a circulating inlet, and the outlet of the delivery pump is further connected with the circulating inlet through a circulating pipeline.
Optionally, an online pH detector is arranged on the circulation pipeline; and/or the buffer unit is provided with a pH value detection mechanism.
Optionally, the buffer unit further includes a fourth inlet, the fourth inlet is connected to the acid liquor conveying pipeline through an acid liquor branch, and a first regulating valve and a flow meter are arranged on the acid liquor branch; and/or the preheater is connected with a steam inlet pipeline and a steam outlet pipeline.
According to another aspect of the present application, there is provided a crystallization process for phenylacetic acid production comprising the steps of:
preheating saline containing sodium phenylacetate, and controlling the preheating temperature;
mixing the preheated saline containing sodium phenylacetate with acid liquor in an acidification mixer to obtain mixed liquor;
conveying the mixed solution to a buffer unit for acidification, and controlling the pH value of an acidified product to obtain an acidified solution;
conveying the acidified solution to a multistage cooling unit to cool the acidified solution to obtain a phenylacetic acid crystallization mixed solution;
the phenylacetic acid crystallization mixture is conveyed to a crystallization unit, where the phenylacetic acid is precipitated in the form of crystals.
Optionally, the method satisfies at least one of the following features: (a) The temperature of the preheated sodium phenylacetate-containing brine is 70-90 ℃, preferably 75-85 ℃, and more preferably 80 ℃; (b) The ratio of the flow of the preheated saline water containing sodium phenylacetate entering the acidification mixer to the flow of the acid liquid entering the acidification mixer is 11:1 to 6:1; (c) the pH value of the acidified product is 1-3, preferably 2; (d) Tail gas generated by the buffer unit is cooled by a graphite heat exchanger and then is recycled, and non-condensable gas generated by the buffer unit is uniformly treated by a waste gas treatment unit; (e) The multistage cooling unit comprises a first-stage cooler, a second-stage cooler and a third-stage cooler, wherein the outlet temperature of the acidizing solution of the first-stage cooler is 45-55 ℃, and preferably 50 ℃; the outlet temperature of the acidified solution of the secondary cooler is 30-40 ℃, and preferably 35 ℃; the outlet temperature of the acidizing solution of the third-stage cooler is 18-22 ℃, and the optimal temperature is 20 ℃; (f) the stirring speed of the crystallization unit is 15-50 rpm.
The technical scheme of the invention at least has the following beneficial effects:
in an embodiment of the present application, a crystallization apparatus for phenylacetic acid production is provided that includes a preheater, an acidification mixer, a buffer unit, a multi-stage cooling unit, and a crystallization unit. In the production process of phenylacetic acid, the mixture obtained after reaction is separated to obtain an oil phase and a water phase, wherein the water phase can be saline containing sodium phenylacetate; the method comprises the steps of preheating brine containing sodium phenylacetate by using a preheater, then mixing the preheated brine containing sodium phenylacetate with acid liquor by using an acidification mixer and a buffer unit respectively, and carrying out acidification reaction and adjustment of solution acidity to obtain an acidified solution; and (3) carrying out multistage cooling on the acidified solution by using a multistage cooling unit, and then conveying the acidified solution to a crystallization unit so as to separate out phenylacetic acid in the crystallization unit in a crystal form. Therefore, based on the design of the device and the connection thereof, the operation and the control are convenient, the quality control of the crystallized product is facilitated, the stability of the product quality is good, the production efficiency can be improved, and the cost is reduced; and is beneficial to ensuring the safety, the production continuity and the stability of the process. Meanwhile, tail gas generated by a buffer unit of the crystallization equipment is recycled through a heat exchange device, and the generated non-condensable gas is treated through a waste gas treatment unit, so that environmental pollution can be avoided, and the crystallization equipment is safe and environment-friendly; and the crystallization equipment adopts a multi-stage cooling unit for cooling, and the cooling mediums adopted by all coolers are different, so that the energy consumption is reduced, and the production cost is saved.
The crystallization method for phenylacetic acid production and the crystallization apparatus for phenylacetic acid production are based on the same inventive concept, and thus have at least all the features and advantages of the crystallization apparatus for phenylacetic acid production, which will not be described herein again.
Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a schematic diagram of a crystallization apparatus for phenylacetic acid production provided in accordance with certain embodiments of the present invention;
figure 2 is a schematic flow diagram of a crystallization process for phenylacetic acid production provided by some embodiments of the present invention.
Description of reference numerals:
1-a preheater; 101-a brine delivery line containing sodium phenylacetate; 102-a steam inlet line; 103-steam outlet pipeline;
2-an acidification mixer; 201-a first inlet; 202-a second inlet; 203-acid liquor conveying pipeline;
3-a buffer unit; 31-an acidification buffer tank; 32-a second stirring mechanism; 301-a third inlet; 302-a fourth inlet; 303-a tail gas outlet; 304-noncondensable gas outlet; 305-a solution outlet; 306-a recycle inlet; 361-acid liquor branch; 362-first regulating valve; 363-a flow meter;
340-an acidified solution delivery line; 341-circulation line; 342-on-line pH detector;
4-a multistage cooling unit; 401-primary cooler; 402-a secondary cooler; 403-three stages of coolers;
5-a crystallization unit; 51-a crystallizing tank; 52-a first stirring mechanism;
6-conveying pump.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.
The terms first, second, third and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that embodiments of the application may be practiced in sequences other than those illustrated or described herein, and that the terms "first," "second," and the like are generally used herein in a generic sense and do not limit the number of terms, e.g., the first term can be one or more than one.
It should be noted that the term "and/or"/"used herein is only one kind of association relationship describing associated objects, and means that there may be three relationships, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
In the description of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "connected," "communicating," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in this application will be understood to be a specific case for those of ordinary skill in the art.
The embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and application scenarios thereof.
In the related art, in the field of phenylacetic acid production, a continuous production mode of phenylacetic acid is provided in order to realize reaction continuity, enlarge production scale, improve product quality or reduce production cost. Illustratively, the phenylacetic acid production system for the continuous production mode of phenylacetic acid comprises: the pretreatment device, the continuous reaction tower (such as a bubble reaction tower), the separation device, the crystallization device and the purification device can also comprise a catalyst recovery device; wherein the purification device can comprise a centrifugal washing device and a drying device; the catalyst recovery device can comprise a standing tank, a catalyst recovery tank and a solvent recovery tower. Specifically, the outlet of the preprocessor can be connected with the inlet of the continuous reaction tower, so that the material from the preprocessor enters the continuous reaction tower to carry out carbonylation synthesis reaction; the outlet of the continuous reaction tower is connected with the inlet of the separation device, and the material obtained after the reaction in the continuous reaction tower enters the separation device for phase separation to obtain a water phase and an oil phase.
An oil phase outlet of the separation device is connected with an inlet of the standing tank, main components of the oil phase comprise a catalyst and a solvent, and the oil phase can be naturally layered after standing in the standing tank; the catalyst discharged from an outlet of the standing tank enters a catalyst recovery tank which can be used for storing the recovered catalyst or further treating the catalyst; the outlet of the catalyst recovery tank is connected with the inlet of the preprocessor, so that the recovered catalyst enters the preprocessor to react again, and the catalyst is recycled; and the solvent discharged from the other outlet of the standing tank enters a solvent recovery tower, so that the solvent can be recycled.
The water phase outlet of the separation device is connected with the inlet of the crystallization device, the water phase separated from the separation device enters the crystallization device to carry out acidification reaction, and then the phenylacetic acid is crystallized; the phenylacetic acid crude product from the crystallization equipment enters a centrifugal washing device, and the precipitate obtained by separation from the centrifugal washing device can enter a drying device for drying so as to obtain a phenylacetic acid product; in addition, the centrifugal mother liquor obtained by separation from the centrifugal washing device can be filtered, the filtered concentrated liquor obtained by filtering can be returned to the crystallization equipment, and the filtered clear liquor obtained by filtering can be subjected to subsequent treatment to obtain a byproduct.
However, as for the background art, the prior phenylacetic acid crystallization method mainly adopts a single crystallization kettle, and the operations such as acidification and crystallization are performed in the crystallization kettle, so that the problems of difficult operation control, high energy consumption, low production efficiency, easy influence on product quality and the like exist, and further improvement is needed. Based on this, the embodiment of the application provides a crystallization device and method for phenylacetic acid production to reach effects such as improving production efficiency, saving manufacturing cost, do benefit to guaranteeing crystallization product quality, convenient operation. See below for a description of specific embodiments.
Referring to fig. 1, in some embodiments of the present application, there is provided a crystallization apparatus for phenylacetic acid production, comprising: a preheater 1, an acidification mixer 2, a buffer unit 3, a multistage cooling unit 4 and a crystallization unit 5.
Wherein, the preheater 1 can be used for preheating the brine containing sodium phenylacetate so as to enable the brine containing sodium phenylacetate to reach a certain temperature, thereby enabling the subsequent acidification reaction to be more complete. The preheater 1 has an inlet and an outlet, the inlet of the preheater 1 is connected to a brine transfer line 101 containing sodium phenylacetate, and a brine containing sodium phenylacetate is fed into the preheater 1 through the brine transfer line 101 containing sodium phenylacetate.
Optionally, the brine containing sodium phenylacetate is derived from the aqueous phase separated from the separation device, and/or is derived from a filtered concentrated solution obtained by filtering and filtering the centrifugal mother liquor separated from the centrifugal washing device. The phenylacetic acid production system described above which comprises a separation unit and a centrifugal washing unit, wherein the aqueous phase and the filtrate concentrate separated via the separation unit are both a brine containing sodium phenylacetate. Alternatively, the brine containing sodium phenylacetate may be the brine from the brine mother liquor tank of the sodium salt recovery process in the phenylacetic acid production system.
In this example, the sodium phenylacetate-containing brine was composed mainly of sodium phenylacetate, sodium chloride, sodium hydroxide and water; the sodium phenylacetate content is relatively high.
In other embodiments, the brine containing sodium phenylacetate may be obtained from other apparatuses depending on the production method of phenylacetic acid, and the solution containing sodium phenylacetate is not limited in this embodiment.
In some embodiments, the brine containing sodium phenylacetate is replaced with a potassium phenylacetate solution or an ammonium phenylacetate solution. It is to be understood that the phenylacetate solution is not limited to the sodium phenylacetate solution, but may be, for example, an ammonium phenylacetate solution, a potassium phenylacetate solution, etc., according to various production modes of phenylacetic acid. The present example is described in detail with reference primarily to the more widely used sodium phenylacetate, however, it is to be understood that the principles of the present invention can be implemented in any suitable phenylacetate.
Optionally, a flow meter is arranged on the saline conveying pipeline 101 containing sodium phenylacetate so as to conveniently meter the flow of the saline containing sodium phenylacetate. Optionally, a delivery pump is disposed on the saline delivery line 101 containing sodium phenylacetate, and the delivery of the saline containing sodium phenylacetate is performed by the delivery pump.
Alternatively, the preheater 1 may be provided with one inlet, and the brine delivery line 101 containing sodium phenylacetate is connected with a brine delivery branch to facilitate the input of sodium phenylacetate brine from different sources into the preheater 1. Alternatively, the preheater 1 may be provided with a plurality of inlets through which sodium phenylacetate brine from different sources may be respectively input into the preheater 1.
The acidification mixer 2 can be used for mixing the preheated brine containing sodium phenylacetate with the acid solution, so that the brine containing sodium phenylacetate and the acid solution can be fully mixed, and the acidification reaction can be fully performed. The acidification mixer 2 comprises a first inlet 201, a second inlet 202 and an outlet, the first inlet 201 of the acidification mixer 2 is communicated with the outlet of the preheater 1, for example, the first inlet 201 of the acidification mixer 2 is connected with the outlet of the preheater 1 through a pipeline; the second inlet 202 of the acidification mixer 2 is connected with an acid liquor conveying pipeline 203, and acid liquor is input into the acidification mixer 2 through the acid liquor conveying pipeline 203. Thus, the preheated brine containing sodium phenylacetate enters the acidification mixer 2 via the first inlet 201, the acid liquor enters the acidification mixer 2 via the acid liquor delivery line 203 and the second inlet 202, and the brine containing sodium phenylacetate and the acid liquor are thoroughly mixed in the acidification mixer 2.
Optionally, the acid solution may be at least one of hydrochloric acid, sulfuric acid, phosphoric acid, or nitric acid. Preferably, the acid solution is hydrochloric acid. The specific type of the acid solution in this embodiment is not limited, and hydrochloric acid may be used, but other types of acids capable of performing an acidification reaction with sodium phenylacetate, such as sulfuric acid, nitric acid, etc., may also be used. Preferably, the acid solution is preferably hydrochloric acid in view of cost, reaction thoroughness or operational feasibility.
Optionally, the hydrochloric acid is 20-37% by mass; further, the hydrochloric acid is 25-35% by mass; further, the hydrochloric acid is hydrochloric acid having a mass concentration of 31%. The specific concentration of hydrochloric acid can be adjusted according to the specific process conditions and the conditions of the sodium phenylacetate-containing brine. In addition, the concentration of other types of acid solutions may be within the above range, or the concentration may be increased or decreased as appropriate.
The buffer unit 3 can be used for fully acidifying the saline water containing sodium phenylacetate and the acid solution and adjusting the acidity of the solution, so that the acidification reaction is more sufficient and thorough, and the pH value of the solution obtained after the acidification reaction meets certain requirements, thereby being more beneficial to subsequent crystallization separation. The buffer unit 3 comprises a third inlet 301, a tail gas outlet 303, a non-condensable gas outlet 304 and a solution outlet 305, the third inlet 301 of the buffer unit 3 is communicated with an outlet of the acidification mixer 2, for example, the third inlet 301 of the buffer unit 3 is connected with an outlet of the acidification mixer 2 through a pipeline, so that the materials mixed in the acidification mixer 2 enter the buffer unit 3. The tail gas outlet 303 of the buffer unit 3 is communicated with a heat exchange device for recovering the tail gas, for example, the tail gas outlet 303 of the buffer unit 3 can be connected with the heat exchange device through a tail gas pipeline, and the tail gas discharged from the buffer unit 3 can contain a small amount of acid liquid such as hydrochloric acid, so that the hydrochloric acid can be recovered after the tail gas is cooled by the heat exchange device; therefore, environmental pollution can be avoided, the recycling of resources can be realized, and the cost is reduced. Noncondensable gas outlet 304 of buffer unit 3 communicates with the exhaust-gas treatment unit who is used for exhaust-gas treatment, if buffer unit 3 noncondensable gas outlet 304 and exhaust-gas treatment unit pass through the exhaust-gas line and are connected, this exhaust-gas treatment unit can be used to handle all waste gases that produce in the phenylacetic acid production, that is, can utilize this exhaust-gas treatment unit to carry out unified recovery processing to the waste gas that produces in the phenylacetic acid production system, like this, can avoid the polluted environment, safety, environmental protection.
The multi-stage cooling unit 4 can be used for cooling the acidified solution obtained after acidification, so that the cooled solution meets the crystallization temperature requirement. This multistage cooling unit 4 includes a plurality of coolers, and a plurality of coolers are series connection in proper order, and the refrigerant that each cooler adopted is all different, and buffer unit 3's solution export 305 and multistage cooling unit 4's entry intercommunication can make the acidizing solution that obtains after the acidizing carry out cooling step by step in multistage cooling unit 4 under the condition that satisfies certain pH value like this to satisfy the crystallization temperature requirement. Through adopting many solutions of a plurality of series connection's coolers to cool off step by step, and the refrigerant (cooling medium) that every cooler adopted all is inequality, helps energy saving like this, reduction in production cost to ensure the cooling effect, more do benefit to the crystallization operation.
Alternatively, the multi-stage cooling unit 4 may be a three-stage cooling unit, i.e. comprising three coolers connected in series. Furthermore, in other embodiments, the multi-stage cooling unit 4 may also be a two-stage cooling unit, i.e. comprising two coolers connected in series; alternatively, the multistage cooling unit 4 may also be a four-stage cooling unit, i.e. comprising four coolers connected in series.
The crystallization unit 5 may be used to crystallize the solution cooled by the multistage cooling unit 4 in the crystallization unit 5 to precipitate phenylacetic acid in the form of crystals. The outlet of the multistage cooling unit 4 communicates with the inlet of the crystallization unit 5, so that the solution cooled by the multistage cooling unit 4 proceeds to the crystallization unit 5, where phenylacetic acid is precipitated in the form of crystals in the crystallization unit 5.
The reaction principle or crystallization process of the crystallization equipment can be as follows: preheating water phase materials from an oil-water separation process in a phenylacetic acid production system, namely brine containing sodium phenylacetate and brine in a brine mother liquor tank in a sodium salt recovery process, wherein the brine contains the sodium phenylacetate and sodium chloride generated by a synthesis reaction; and then, excessive hydrochloric acid is added into the acidification mixer 2 and the acidification buffer unit 3 to acidify sodium phenylacetate to generate phenylacetic acid, and the phenylacetic acid is insoluble in water when the pH value is less than 2, so that the crystallization separation is facilitated. During the acidification reaction, hydrochloric acid needs to be kept slightly excessive, the acidified solution obtained after acidification enters a crystallization unit 5 after being cooled by a multi-stage cooling unit 4, and phenylacetic acid is separated out of crystals in the crystallization unit 5 and moves to the bottom of equipment. The process involves the following reaction formula:
C 6 H 5 CH 2 COONa+HCl→C 6 H 5 CH 2 COOH+NaCl。
based on the above arrangement, the crystallization device for phenylacetic acid production provided by this embodiment can be applied to the phenylacetic acid production field, and can implement acidification and crystallization treatment of sodium phenylacetate generated in the phenylacetic acid production process. The mode that it adopts preheating, acidizing to mix, acidizing buffering, multistage cooling and crystallization unit 5 to be connected can avoid single crystallization kettle operation technology index fluctuation great, be unfavorable for operation scheduling problem, can improve production efficiency, makes things convenient for operation control, does benefit to the quality control to the crystallization product, and product quality stability is good, can improve production efficiency, reduce cost. Meanwhile, tail gas generated by the buffer unit 3 of the crystallization equipment is recycled through the heat exchange device, and the generated non-condensable gas is treated through the waste gas treatment unit, so that the environmental pollution can be avoided, the method is safe and environment-friendly, and the resource can be recycled; in addition, the crystallization equipment adopts the multistage cooling unit 4 for cooling, and the coolants adopted by all coolers are different, so that the energy consumption is favorably reduced, and the production cost is saved.
In addition, the crystallization equipment for phenylacetic acid production is applied to a phenylacetic acid production system, so that the problems existing in the intermittent production process at present can be solved, the continuous, stable and balanced production of the production system is facilitated, the automatic control is convenient to adopt, the energy consumption is low, the production cost can be saved, the production efficiency is improved, the safety, the production continuity and the stability of the process can be better ensured, the purity of the product is ensured, and the economic benefit and the social benefit are remarkable.
In some embodiments, the multistage cooling unit 4 is a three-stage cooling unit, that is, the multistage cooling unit 4 includes three coolers connected in series, the three coolers connected in series are a first-stage cooler 401, a second-stage cooler 402 and a third-stage cooler 403, that is, the first-stage cooler 401, the second-stage cooler 402 and the third-stage cooler 403 are connected in series in sequence; wherein, the inlet of the primary cooler 401 is communicated with the solution outlet 305 of the buffer unit 3, the outlet of the primary cooler 401 is connected with the inlet of the secondary cooler 402, the outlet of the secondary cooler 402 is connected with the inlet of the tertiary cooler 403, and the outlet of the tertiary cooler 403 is communicated with the inlet of the crystallization unit 5.
By adopting a three-stage cooling mode, the rapid crystallization of phenylacetic acid and the blockage of equipment can be avoided, and different refrigerants can be conveniently utilized to realize energy conservation and reduce energy consumption. In addition, the adoption of the three-stage cooling mode not only helps to ensure the cooling effect and the crystallization effect, but also has relatively low cost and is convenient to distribute and control.
In some embodiments, the temperature of the refrigerant of the primary cooler 401 is higher than the temperature of the refrigerant of the secondary cooler 402, and the temperature of the refrigerant of the secondary cooler 402 is higher than the temperature of the refrigerant of the tertiary cooler 403. In the multi-stage cooling process, the temperature of the later stage cooling is lower than that of the earlier stage cooling. In contrast, the primary cooler 401 is close to the buffer unit 3, and the tertiary cooler 403 is close to the crystallization unit 5; the acidified solution exiting primary cooler 401 is at a higher temperature than the acidified solution exiting secondary cooler 402 and the acidified solution exiting secondary cooler 402 is at a higher temperature than the acidified solution exiting tertiary cooler 403. Like this, through the cooling step by step, can avoid phenylacetic acid rapid crystallization to do benefit to the quality of guaranteeing the crystallization product.
In some embodiments, temperature adjusting valves are disposed on refrigerant connecting pipelines of the primary cooler 401, the secondary cooler 402, and the tertiary cooler 403. In order to facilitate the control and adjustment of the temperature of the coolant of each cooler, a temperature adjusting valve can be arranged on the coolant connecting pipeline of each cooler to realize the respective control of different coolant temperatures, so as to obtain the required corresponding temperature of the cooled acidified solution. Illustratively, the primary cooler 401 is connected to a first refrigerant inlet pipeline and a first refrigerant outlet pipeline, and a first temperature regulating valve is arranged on the first refrigerant inlet pipeline and/or the first refrigerant outlet pipeline; the secondary cooler 402 is connected with a second refrigerant inlet pipeline and a second refrigerant outlet pipeline, and a second temperature regulating valve is arranged on the second refrigerant inlet pipeline and/or the second refrigerant outlet pipeline; the tertiary cooler 403 is connected to a third refrigerant inlet pipeline and a third refrigerant outlet pipeline, and a third temperature adjusting valve is arranged on the third refrigerant inlet pipeline and/or the third refrigerant outlet pipeline.
In some embodiments, the refrigerant of the primary cooler 401 is process circulating water with a temperature of 25 ℃ to 35 ℃, and the process circulating water is process circulating water generated in the whole phenylacetic acid production process; the refrigerant of the secondary cooler 402 is centrifugal mother liquor with the temperature of 10-20 ℃, and the centrifugal mother liquor is centrifugal mother liquor separated by centrifugal equipment (a centrifugal washing device) in a phenylacetic acid production system; the refrigerant of the third-stage cooler 403 is chilled water with the temperature of 3-7 ℃.
The refrigerant adopted by the first-stage cooler 401 is process circulating water, the refrigerant adopted by the second-stage cooler 402 is centrifugal mother liquor, and the refrigerant adopted by the third-stage cooler 403 is chilled water. The acidified solution is subjected to forced heat exchange with process circulating water in a first-stage cooler 401, is subjected to forced heat exchange with centrifugal mother liquor in a second-stage cooler 402, and is subjected to forced heat exchange with chilled water in a third-stage cooler 403.
Therefore, the acidified solution is gradually cooled and crystallized through the three-stage cooling unit, and various cooling liquids in the process are reasonably utilized by adopting different refrigerants, so that the energy consumption is saved, the cost is reduced, the resource recycling is realized, and the method is safe and environment-friendly.
Optionally, the first-stage cooler 401, the second-stage cooler 402, and the third-stage cooler 403 are all plate heat exchangers. The plate cooler may be a specially designed heat exchanger. Therefore, the heat exchanger has the advantages of simple structure, low cost and good heat exchange effect.
The first-stage cooler 401, the second-stage cooler 402 and the third-stage cooler 403 can all adopt plate heat exchangers and are vertically arranged, a refrigerant enters from the lower part of the heat exchanger and exits from the upper part of the heat exchanger, and the refrigerant and the acidizing solution form countercurrent heat exchange. The plate heat exchanger has the advantages of easy manufacture, low production cost, convenient cleaning, strong adaptability, large treatment capacity and the like.
In some embodiments, the crystallization unit 5 includes a crystallization tank 51 and a first stirring mechanism 52 provided to the crystallization tank 51. The first stirring mechanism 52 may be a stirrer with variable frequency control. Clogging of the apparatus can be avoided or crystallization efficiency can be improved by providing the first stirring mechanism 52 in the crystallization tank 51.
Optionally, the bottom of crystallizer 51 is provided with the mixed liquid export of phenylacetic acid crystallization, and this phenylacetic acid crystallization mixed liquid exit linkage has the mixed liquid pipeline of phenylacetic acid crystallization, is provided with flow control valve on the mixed liquid pipeline of phenylacetic acid crystallization. The obtained phenylacetic acid crystallization mixed liquid can be conveyed to the next working procedure for treatment through the phenylacetic acid crystallization mixed liquid conveying pipeline, and the conveying flow of the phenylacetic acid crystallization mixed liquid can be controlled through the flow control valve.
In some embodiments, the buffer unit 3 includes an acidification buffer tank 31 and a second stirring mechanism 32 disposed at the acidification buffer tank 31. The second stirring mechanism 32 may be a stirrer with variable frequency control. The second stirring mechanism 32 is arranged in the acidification buffer tank 31, so that the materials can be mixed more fully, and the acidification efficiency is improved.
Optionally, the bottom of the acidification buffer tank 31 is provided with a solution outlet 305.
In some embodiments, the solution outlet 305 of the acidification buffer tank 31 is connected to the inlet of the multi-stage cooling unit 4 through an acidification solution conveying pipeline 340, that is, the solution outlet 305 of the acidification buffer tank 31 is connected to the inlet of the primary cooler 401 through the acidification solution conveying pipeline 340. The acidizing solution conveying pipeline 340 is provided with a conveying pump 6 (circulating pump); the buffer unit 3 further comprises a circulation inlet 306, and the outlet of the delivery pump 6 is further connected to the circulation inlet 306 through a circulation line 341. That is, the acidified solution flowing out of the solution outlet 305 of the acidified buffer tank 31 can be returned to the acidified buffer tank 31 for circulation through the transfer pump 6 and the circulation line 341, so as to facilitate the adjustment of the pH value of the solution; when the solution meets a certain pH value, the acidified solution flowing out of the solution outlet 305 of the acidified buffer tank 31 can be transported to the multistage cooling unit 4 by the transport pump 6 for cooling.
In order to adjust the pH value of the acidified solution, the acidified solution is conveyed to the multistage cooling unit 4 for cooling after meeting a certain requirement, and the circulation line 341 is further provided in this embodiment, so that the acidified solution can be circulated by the conveying pump 6 and the circulation line 341, and the pH value is adjusted by adding acid solution to the acidification buffer tank 31, so that the acidified solution meets the requirement. Therefore, the structure is simple, the adjustment and the control are convenient, and the feasibility is strong.
Optionally, the delivery pump 6 is a horizontal axial-flow pump, and the pump impeller of the type has a small damage effect on crystal particles, so that the completion of the crystal particles can be ensured. Further, the solution was forcibly circulated by the transfer pump 6, and the crystal grain size was also made uniform. Optionally, the delivery pump 6 is provided with a frequency converter, and the circulation amount can be adjusted by adjusting the frequency of the pump.
In some embodiments, an online pH detector 342 is disposed on the circulation line 341; and/or the buffer unit 3 is provided with a pH value detection mechanism. That is, the on-line pH detector 342 may be disposed on the circulation line 341, so as to facilitate operation and control, directly observe the pH of the solution on the circulation line 341, and further facilitate adjustment of the pH of the solution. Alternatively, a pH detection mechanism, such as a pH sensor, may be disposed on the acidification buffer tank 31 for monitoring the pH of the acidified solution. Alternatively, an on-line pH detector 342 may be disposed on the circulation line 341, and a pH detection mechanism may be disposed on the acidification buffer tank 31 to monitor the pH of the solution in multiple directions.
Optionally, the pH of the acidified solution obtained after acidification is generally required to be between 1 and 3, more preferably around 2.
In some embodiments, the buffer unit 3 further includes a fourth inlet 302, the fourth inlet 302 is connected to the acid liquid conveying line 203 through an acid liquid branch 361, and a first regulating valve 362 and a flow meter 363 are disposed on the acid liquid branch 361.
Optionally, a second regulating valve is disposed on the acid liquid conveying pipeline 203 for regulating the flow rate of the acid liquid entering the acidification mixer 2.
Optionally, a flow meter is also arranged on the acid liquor conveying pipeline 203 to facilitate the flow rate measurement of the acid liquor. Optionally, a delivery pump is disposed on the acid liquid delivery pipeline 203, and the acid liquid is delivered through the delivery pump. Optionally, the acid liquor conveying pipeline 203 is connected to an acid liquor storage tank.
In order to adjust the pH value of the acidified solution, acid solution needs to be added into the acidification buffer tank 31 to adjust the pH value, so that the pH of the solution meets certain requirements and then is conveyed to the multistage cooling unit 4 for cooling. Based on this, a fourth inlet 302 may be further disposed on the acidification buffer tank 31, the fourth inlet 302 is connected to the acid liquor conveying pipeline 203 through the acid liquor branch 361, and the acid liquor conveying pipeline 203 is connected to the acid liquor storage tank. Therefore, on one hand, the acid liquor in the acid liquor storage tank can enter the acidification mixer 2 through the acid liquor conveying pipeline 203 to be mixed with the preheated sodium phenylacetate brine; on the other hand, the acid solution enters the acidification buffer tank 31 through the acid solution branch 361 to adjust the pH value of the solution. Further, in order to facilitate the adjustment and measurement of the acid liquid flow, a first adjusting valve 362 and a flow meter are arranged on the acid liquid branch 361; in addition, a second regulating valve and a flow meter may be disposed on the acid liquid delivery line 203.
In some embodiments, the heat exchange device comprises a graphite heat exchanger.
In this embodiment, the tail gas outlet 303 of the buffer unit 3 is connected to the graphite heat exchanger through a tail gas pipeline, and the tail gas is cooled by the graphite heat exchanger, so that an acid solution such as hydrochloric acid can be recovered. Because the tail gas discharged by the buffer unit 3 contains a small amount of acid liquid such as hydrochloric acid, the hydrochloric acid can be recovered after the tail gas is cooled by the graphite heat exchanger; therefore, environmental pollution can be avoided, the recycling of resources can be realized, and the cost is reduced. In addition, the graphite heat exchanger cools the tail gas, so that the heat exchange efficiency is high and the cost is low.
In some embodiments, the preheater 1 is connected to a steam inlet line 102 and a steam outlet line 103. That is, the heat exchange medium of the preheater 1 is steam, and brine containing sodium phenylacetate is preheated by the steam.
Optionally, a steam regulating valve is disposed on the steam inlet pipeline 102 and/or the steam outlet pipeline 103.
Alternatively, the preheater 1 may employ a spiral plate heat exchanger. The spiral plate type heat exchanger flow channel is generally rectangular with a uniform cross section, no flow dead zone exists in the fluid in the channel, the heat exchange coefficient is large, and the heat exchange effect is good; in addition, the self-cleaning device has strong self-cleaning capability and small occupied area, and can accurately control the outlet temperature of the material.
In some embodiments, as shown in fig. 1 and 2, the present embodiments also provide a crystallization process for phenylacetic acid production, comprising the steps of:
preheating saline water containing sodium phenylacetate, and controlling the preheating temperature;
mixing the preheated saline water containing sodium phenylacetate with acid liquor in an acidification mixer 2 to obtain mixed liquor;
conveying the mixed solution to a buffer unit 3 for acidification, and controlling the pH value of an acidified product to obtain an acidified solution;
conveying the acidified solution to a multistage cooling unit 4 to cool the acidified solution to obtain a phenylacetic acid crystallization mixed solution;
the phenylacetic acid crystallization mixed liquid is sent to a crystallization unit 5, and in the crystallization unit 5, phenylacetic acid is precipitated in the form of crystals.
It should be understood that the crystallization method for phenylacetic acid production and the aforementioned crystallization device for phenylacetic acid production are based on the same inventive concept, and with respect to the structure of the apparatus, the connection thereof, and the like, reference may be made to the aforementioned description of the crystallization device for phenylacetic acid production, and the crystallization method for phenylacetic acid production has at least all the features and advantages of the aforementioned crystallization device for phenylacetic acid production, and thus will not be described herein again.
In the crystallization method for phenylacetic acid production, in order to realize full acidification and accelerate acidification speed, brine containing sodium phenylacetate needs to be heated and preheated; meanwhile, in order to ensure the crystallization quality and avoid crystallization in the acidification stage, the temperature after acidification reaction is not lower than about 76.5 ℃ of the melting temperature of phenylacetic acid. Thus, prior to acidification, the brine containing sodium phenylacetate is heated to a temperature of 70 ℃ to 90 ℃, preferably 75 ℃ to 85 ℃ by means of preheater 1, and then acidified with an acid solution such as hydrochloric acid. Part of the acid solution is mixed with the preheated saline water containing sodium phenylacetate through the acidification mixer 2 and then enters the acidification buffer unit 3 together, the stirring mechanism is arranged in the buffer unit 3, the materials can be fully mixed and reacted through slow stirring, and the pH value of the acidification solution obtained after the final reaction is controlled to be about 1-3, more preferably about 2 through adding the acid solution. The material after qualified reaction can be conveyed to the cooling unit from the bottom of the buffer unit 3.
The temperature of the acidified solution from the buffer unit 3 is generally above 70 ℃, the phenylacetic acid is in a molten state, and the final solution can be cooled in multiple stages through the multistage cooling unit 4, so that the temperature of the final solution is 18-22 ℃, and is preferably about 20 ℃; the phenylacetic acid is then crystallized and precipitated in the transfer to the crystallization unit 5. The arrangement of the multistage cooling unit 4 can avoid the rapid crystallization of phenylacetic acid and the blockage of equipment, and is convenient for utilizing different refrigerants to realize energy conservation and reduce energy consumption. The lower the final crystallization temperature, the less phenylacetic acid is dissolved in the solution, and the amount of phenylacetic acid to be introduced into the subsequent step can be reduced.
Optionally, the crystallization method may further include a step of separating the crystals. The separation step may be any solid-liquid separation method, such as centrifugation, filtration, and the like.
In some embodiments, the temperature of the preheated sodium phenylacetate-containing brine is from 70 ℃ to 90 ℃, preferably from 75 ℃ to 85 ℃, preferably from 80 ℃ to 85 ℃, and more preferably 80 ℃. Illustratively, the temperature of the preheated sodium phenylacetate-containing brine may be 70 ℃, 72 ℃, 75 ℃, 78 ℃, 79 ℃, 80 ℃, 81 ℃, 82 ℃, 85 ℃, 90 ℃ and the like. By keeping the preheating temperature of the sodium phenylacetate-containing brine (i.e., the outlet temperature of the preheater 1) within the above range, particularly around 80 ℃, the subsequent acidification reaction can be more complete, which is beneficial to improving the acidification effect.
In some embodiments, the ratio of the flow rate of the preheated saline containing sodium phenylacetate into the acidification mixer to the flow rate of the acid solution into the acidification mixer is 11:1 to 6:1. for example, the ratio of the flow rate of the preheated sodium phenylacetate-containing brine to the flow rate of the acid solution to the acidification mixer 2 may be 11: 1. 10: 1. 9: 1. 8: 1. 7: 1. 6:1, etc. The specific flow ratio of the two can be determined according to the concentration of acid liquid such as hydrochloric acid or other relevant process conditions.
In some embodiments, the pH of the acidified product, i.e. the acidified solution, is 1 to 3, preferably 2.
In some embodiments, the tail gas generated by the buffer unit 3 is cooled by a graphite heat exchanger and then is subjected to acid liquor recovery, and the non-condensable gas generated by the buffer unit 3 is subjected to unified recovery processing by an exhaust gas treatment unit.
In some embodiments, multi-stage cooling unit 4 includes a primary cooler 401, a secondary cooler 402, and a tertiary cooler 403. The refrigerant of the primary cooler 401 is process circulating water with the temperature of 25-35 ℃, and the process circulating water is process circulating water generated in the whole phenylacetic acid production process; the outlet temperature of the acidified solution from primary cooler 401 is 45 ℃ to 55 ℃, and may be 48 ℃ to 52 ℃, preferably 50 ℃. The refrigerant of the secondary cooler 402 is centrifugal mother liquor with the temperature of 10-20 ℃, and the centrifugal mother liquor is centrifugal mother liquor separated by centrifugal equipment (a centrifugal washing device) in a phenylacetic acid production system; the outlet temperature of the acidified solution from secondary cooler 402 is 30 c to 40 c, and may be 33 c to 37 c, preferably 35 c. The refrigerant of the third-stage cooler 403 is chilled water with the temperature of 3-7 ℃; the outlet temperature of the acidified solution from tertiary cooler 403 is 18 c to 22 c, and may be 19 c to 21 c, preferably 20 c.
In the multi-stage cooling unit 4, the outlet temperature of each cooler may fluctuate to some extent, but the fluctuation range is preferably within ± 2 ℃, and more preferably within ± 1 ℃.
In some embodiments, the stirring rate of the crystallization unit is 15 to 50rpm, and further may be 20 to 40rpm.
In some embodiments, the stirring rate of the buffer unit is 15 to 50rpm, and further may be 20 to 40rpm.
Example 1
The water phase (brine containing sodium phenylacetate) separated from the separation device and the brine (mainly comprising sodium phenylacetate, sodium chloride, sodium hydroxide and water) in the brine mother liquor tank of the sodium salt recovery process are metered and then enter the preheater 1 to be heated to about 80 ℃, and the temperature of the preheater 1 can be automatically controlled by a steam regulating valve. The preheated saline containing sodium phenylacetate and hydrochloric acid (the mass concentration is 31 percent) are mixed according to the weight ratio of 8: the ratio of 1 is respectively fed into an acidification mixer 2, and the mixture is mixed in the acidification mixer 2. The mixed feed liquid enters an acidification buffer tank 31 with stirring (stirring with variable frequency control), the stirring speed of the acidification buffer tank 31 is 50rpm, more sufficient mixing and acidification reaction are carried out in the acidification buffer tank 31, the acidity of the solution is regulated, a fourth inlet 302 of the acidification buffer tank 31 is connected with an acid conveying pipeline 203 through an acid branch 361, and the flow rates of hydrochloric acid entering an acidification mixer 2 and hydrochloric acid entering the acidification buffer tank 31 can be respectively and automatically controlled through regulating valves. Hydrochloric acid is recovered after tail gas at the top of the acidification buffer tank 31 is cooled by a graphite heat exchanger, and noncondensable gas generated by the acidification buffer tank 31 is conveyed to a tail gas treatment unit for unified recovery treatment. The acidified solution in the acidified buffer tank 31 is circulated by a delivery pump 6, an online pH detector 342 is arranged on a circulation pipeline 341 to measure the online pH of the acidified solution, the pH is adjusted by adjusting the amount of hydrochloric acid by a first adjusting valve 362 on an acid solution branch 361, the acidified solution is qualified after the pH is about 2, and the acidified solution is pumped into a third-stage cooling unit by the delivery pump 6, and is gradually cooled by three coolers in series (the coolers are all specially designed plate heat exchangers), wherein the first-stage cooler 401 (the refrigerant is production process circulating water with the temperature of 25-35 ℃, the solution outlet temperature is 50 ℃, and is controlled by a temperature adjusting valve), the second-stage cooler 402 (the refrigerant is centrifugal mother liquid with the temperature of 10-20 ℃, and the solution outlet temperature is about 35 ℃), and the third-stage cooler 403 (the refrigerant is chilled water with the temperature of 3-7 ℃, the solution outlet temperature is 20 ℃, and is controlled by the temperature adjusting valve). The cooled feed liquid was introduced into a crystallizer 51 with stirring (stirring with variable frequency control), and the phenylacetic acid was crystallized and precipitated at a stirring speed of 30rpm in the crystallizer 51. The phenylacetic acid crystallization mixed liquid obtained from the cooling tank can be controlled by a flow regulating valve to be sent to subsequent processes such as a product centrifuge for centrifugal separation.
In conclusion, the crystallization equipment and the crystallization method for phenylacetic acid production provided by the embodiment have the advantages of low energy consumption, capability of saving production cost, improvement on production efficiency, convenience in operation, capability of avoiding environmental pollution, safety, environmental friendliness, capability of better ensuring the safety, production continuity and stability of the process and product purity, stable product quality and remarkable economic and social benefits.
This detailed description is not a part of the technology that is well known to those skilled in the art.
While the present embodiments have been described with reference to the accompanying drawings, it is to be understood that the present embodiments are not limited to those precise embodiments, which are intended to be illustrative rather than restrictive, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope of the appended claims.
Claims (10)
1. A crystallization apparatus for phenylacetic acid production, comprising:
the inlet of the preheater is connected with a brine conveying pipeline containing sodium phenylacetate;
the acidification mixer comprises a first inlet and a second inlet, the first inlet is communicated with the outlet of the preheater, and the second inlet is connected with an acid liquor conveying pipeline;
the buffer unit comprises a third inlet, a tail gas outlet, a non-condensable gas outlet and a solution outlet, the third inlet is communicated with the outlet of the acidification mixer, the tail gas outlet is communicated with a heat exchange device for recovering tail gas, and the non-condensable gas outlet is communicated with a waste gas treatment unit for waste gas treatment;
the multi-stage cooling unit comprises a plurality of coolers connected in series, the coolers adopt different refrigerants, and a solution outlet of the buffer unit is communicated with an inlet of the multi-stage cooling unit;
a crystallization unit, wherein an outlet of the multistage cooling unit is communicated with an inlet of the crystallization unit, and phenylacetic acid is precipitated in a crystal form in the crystallization unit.
2. The crystallization apparatus for production of phenylacetic acid according to claim 1, wherein the multistage cooling unit comprises three coolers connected in series, the three coolers connected in series are a primary cooler, a secondary cooler and a tertiary cooler, respectively, an inlet of the primary cooler is communicated with the solution outlet of the buffer unit, and an outlet of the tertiary cooler is communicated with an inlet of the crystallization unit.
3. The crystallization equipment for phenylacetic acid production according to claim 2, wherein the temperature of the refrigerant of the primary cooler is higher than the temperature of the refrigerant of the secondary cooler, and the temperature of the refrigerant of the secondary cooler is higher than the temperature of the refrigerant of the tertiary cooler;
and/or temperature regulating valves are arranged on refrigerant connecting pipelines of the primary cooler, the secondary cooler and the tertiary cooler.
4. The crystallization equipment for phenylacetic acid production according to claim 2, wherein the refrigerant of the primary cooler is process circulating water with a temperature of 25-35 ℃, and the process circulating water is process circulating water generated in the whole phenylacetic acid production process;
the refrigerant of the secondary cooler is centrifugal mother liquor with the temperature of 10-20 ℃, and the centrifugal mother liquor is centrifugal mother liquor separated by centrifugal equipment in a phenylacetic acid production system;
the refrigerant of the third-stage cooler is chilled water with the temperature of 3-7 ℃.
5. The crystallization apparatus for production of phenylacetic acid according to claim 1, wherein the crystallization unit comprises a crystallization tank and a first stirring mechanism provided in the crystallization tank;
and/or the buffer unit comprises an acidification buffer tank and a second stirring mechanism arranged on the acidification buffer tank;
and/or the heat exchange device comprises a graphite heat exchanger.
6. The crystallization equipment for phenylacetic acid production according to claim 1, wherein a solution outlet of the buffer unit is connected with an inlet of the multistage cooling unit through an acidified solution conveying pipeline, and a conveying pump is arranged on the acidified solution conveying pipeline;
the buffer unit further comprises a circulating inlet, and the outlet of the delivery pump is further connected with the circulating inlet through a circulating pipeline.
7. The crystallization apparatus for production of phenylacetic acid according to claim 6, wherein an on-line pH value meter is provided on the circulation line;
and/or the buffer unit is provided with a pH value detection mechanism.
8. The crystallization device for phenylacetic acid production according to any one of claims 1 to 7, wherein the buffer unit further comprises a fourth inlet, the fourth inlet is connected to the acid liquid delivery line through an acid liquid branch, and the acid liquid branch is provided with a first regulating valve and a flow meter;
and/or the preheater is connected with a steam inlet pipeline and a steam outlet pipeline.
9. A crystallization process for phenylacetic acid production comprising the steps of:
preheating saline water containing sodium phenylacetate, and controlling the preheating temperature;
mixing the preheated saline containing sodium phenylacetate with acid liquor in an acidification mixer to obtain mixed liquor;
conveying the mixed solution to a buffer unit for acidification, and controlling the pH value of an acidified product to obtain an acidified solution;
conveying the acidified solution to a multistage cooling unit to cool the acidified solution to obtain a phenylacetic acid crystallization mixed solution;
the phenylacetic acid crystallization mixture is conveyed to a crystallization unit where the phenylacetic acid is precipitated in the form of crystals.
10. The crystallization process for the production of phenylacetic acid according to claim 9, wherein said process satisfies at least one of the following characteristics:
(a) The temperature of the preheated sodium phenylacetate-containing brine is 70-90 ℃, preferably 75-85 ℃, and more preferably 80 ℃;
(b) The ratio of the flow of the preheated brine containing sodium phenylacetate entering the acidification mixer to the flow of the acid liquid entering the acidification mixer is 11:1 to 6:1;
(c) The pH value of the acidified product is 1-3, preferably 2;
(d) Tail gas generated by the buffer unit is cooled by a graphite heat exchanger and then acid liquor is recovered, and non-condensable gas generated by the buffer unit is uniformly treated by a waste gas treatment unit;
(e) The multistage cooling unit comprises a first-stage cooler, a second-stage cooler and a third-stage cooler, wherein the outlet temperature of the acidified solution of the first-stage cooler is 45-55 ℃, and preferably 50 ℃; the outlet temperature of the acidified solution of the secondary cooler is 30-40 ℃, and preferably 35 ℃; the outlet temperature of the acidizing solution of the third-stage cooler is 18-22 ℃, and the optimal temperature is 20 ℃;
(f) The stirring speed of the crystallization unit is 15-50 rpm.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1030451A (en) * | 1965-01-26 | 1966-05-25 | Newton Chambers Engineering Lt | Improvements relating to the purification of benzene |
| CN106365976A (en) * | 2016-08-31 | 2017-02-01 | 河北诚信有限责任公司 | Phenylacetic acid continuous production process |
| CN113354528A (en) * | 2021-06-07 | 2021-09-07 | 李乾华 | Production method of phenylacetic acid |
| CN113548954A (en) * | 2021-07-30 | 2021-10-26 | 四川信乙化工有限公司 | Phenylacetic acid preparation system |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1030451A (en) * | 1965-01-26 | 1966-05-25 | Newton Chambers Engineering Lt | Improvements relating to the purification of benzene |
| CN106365976A (en) * | 2016-08-31 | 2017-02-01 | 河北诚信有限责任公司 | Phenylacetic acid continuous production process |
| CN113354528A (en) * | 2021-06-07 | 2021-09-07 | 李乾华 | Production method of phenylacetic acid |
| CN113548954A (en) * | 2021-07-30 | 2021-10-26 | 四川信乙化工有限公司 | Phenylacetic acid preparation system |
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